Over the past 20 years or so, standard hardsided luggage cases included two vacuum formed shells of a thermoplastic sheet, usually an ABS (acrylonitrile butidiene styrene) polymer. These shells were usually fastened to a pair of aluminum or magnesium frames. Accessories such as wheels and handles were also attached to the frame or directly to the shells. A drawback of such ABS shell luggage was that the corner portions, that is the areas of the generally rectangular shells at the intersection of the generally planar major face and two of the other faces, tended to be relatively thin in comparison to the other portions of the thermoformed shell. This is because, inherent to the vacuum forming process, the material is stretched thin in these corner regions during the deflection of the heated, rubbery ABS sheet into the female vacuum form. Consequently, the preform sheet tended to be made of a heavier material in order to anticipate this thinning and to compensate for the thinning so that the corner regions were adequately constructed. Despite these precautions, the vacuum formed shells are subject to failure in the corner regions since a luggage case tends to take considerable abuse concentrated at the corners.
Also as a result of making luggage of a relatively thicker ABS material, the weight of the overall luggage case tended to be high, since the thickness of the ABS material in the central portion of the shells were thicker than really necessary to provide adequate strength.
Also, considerable effort has been expended to provide a scuff resistant surface to the outside of the thermoformed shells. A printed capsheet of an especially abrasion-resistant material is normally laminated onto the thermoplastic ABS substrate.
The superior durability and scuff resistance of a fabric covered shell has been well known. In an attempt to capitalize on this phenomenon, ABS shell luggage has been covered with fabric. One such product, marketed under the trademark SILHOUETTE SUPRA by SAMSONITE CORPORATION, the assignee of the subject invention, consisted of a conventional thermoformed shell, but without the decorative printed capsheet. To this shell was adhesively fastened a tailored covering of fabric consisting of a fabric rail portion (sized to cover the periphery side walls of the shell), which is in turn sewn to a large panel of fabric for covering the major face of the shell. While the aesthetic desirability of the resulting fabric covered shell was apparent, this product was expensive to manufacture and was quite heavy. The manual operations involved in sewing the fabric covering, coating the outside of the thermoformed shell with adhesive and pulling the thus sewn covering over the ABS shell took considerable time and effort. While the scuff resistance inherent in the fabric covering helped increase one aspect of the durability of the luggage, the vulnerability of the shells to crack in the corner regions on extreme impact remained unresolved.